by By Chris Woodyard and John Bacon, USA TODAY

No damage was reported from the quake that struck at 6:25 a.m. PT. The magnitude-4.4 earthquake had initially been rated at 4.7, but was downgraded about 20 minutes after the jolt, the U.S. Geological Survey said.

Still, even some locals were alarmed.

"I live in Westwood. It was really scary w/a few big jolts. It felt like it wouldn't end and the sound was horrible," tweeted ImSusanT.

@iRachelBrill had this take: "the initial jolt felt like the 94 Northridge quake only without the after roll. Now im@waiting for the aftershocks..." The Northridge earthquake in 1994 left 57 people dead and thousands injured.

Monday's quake was centered in the San Fernando Valley, about 6 miles north-northwest from Westwood, an enclave in west Los Angeles, the agency said. Westwood is the home to the University of California, Los Angeles - UCLA. The location would put it close to the community of Encino. The depth was 5 miles below the surface and it occurred on the north edge of the Santa Monica mountains, the USGS said.

It was the largest earthquake to strike near Los Angeles in years. The quake lasted several seconds, shaking furniture and causing ripples in swimming pools just as many Southern Californians were awaking.

Los Angeles police sent out a tweet asking residents not to call 911 to report the earthquake. "We are well aware of it. Lines need to be kept open for emergencies," the message said. The Los Angeles County Metropolitan Transportation Authority, which operates the region's massive bus and rail system, said that operations were returning to normal after some quick checks to look for damage just as the morning commute was starting.

"We have no reports of damage," said USGS seismologist Robert Graves at a press conference. Damage, given the intensity of the quake, "would be slight if it occurred at all." He said one aftershock of magnitude 2.7 had occurred and there was a 5% chance that the shaker was a foreshock to a larger quake.

Co-anchors of a local KTLA broadcast were sufficiently concerned when it hit -- host Chris Schauble pointed at the ceilingand said "Earthquake! We're having an earthquake!" right before he and his co-host Megan Henderson dove under the newsdesk.

Being Los Angeles, the quake, of course, brought quick reaction from celebrities.